Tool for grinding valve seats



Nov. 5, 1929. G. wAcKr-:R ET Al.- l v 1,734,548

TOOL FOR GRINDING VALVE SEATS Filed My 31, 1927 @@abm am@ Patented Nov. 5,l 1929 UNITED STATES PATENT OFFICE FREDERICK G. WACKER AND HERMAN W. ZIMMERMAN, OF CHICAGO, ILLINOIS, AS-

SIGNORS T0 AUTOMOTIVE MAINTENANCE MACHINERY CO., OF CHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIS TOOL FOR GRINDING VALVE SEATS Application led May 31,

Our invention relates to a tool for grinding valve-seats, and more particularly the conical seats for poppet-Valves of automobile gasengines and the like.

Among the objects of our invention are, to provide a tool having its abrading element detachable for ready renewal and so constructed and arranged that its metallic parts are simple, inexpensive, and easy to operate, its renewable abrasive members are of advantageous and inexpensive construction, and itsl correlation of the permanent metallic parts and the renewable abrasive elements may effectually insure that the tool can be readily7 conditioned for operation and will work with eiiciency and precision.

For attaining these objects, and others that will become apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawings, our invention consists in the features of construction and combinations of parts hereinafter set forth and claimed.

In the drawing, wherein we have illustrated a desirable and preferred embodiment of our invention, for purposes of full disclosure- Fig. 1 is a side elevation of a tool, with parts broken in section, the members of the tool being loosely placed together as in course of assembly;

Fig. 2 is a similar view with the members tightly assembled, as for use;

Fig. 3 is a perspective detail of a renewable abrasive element; and

Fig. 4 is a perspective detail of a disk from which an abrasive element is made, the layers of said disk being partly spread open and folded back.

The body structure, 10, of the tool, carries a grinding head 11 and an abutment 12, one of them being removable from the shank 13 so that the replaceable abrading element 14 may be clamped between them. Specifically, the body 10 is shown as comprising, preferably in an integral structure machined from a suitable forging, a lower guide-stem y 15 merging into the stout abutment-ange 12 which is flat on its upper surface and is concentric with the stem 15 and .the shank 13. The shank, having any suitable driving-pro- 1927. Serial No. 195,217.

vision at its upper end for hand or power drive, has a threaded portion 16 and below it a slightly enlarged guide-cylinder portion 1'( at the bottom of which is a groove 18 encircling the shank where it joins the flangeabutment 12. The grinding-head or cone member, 11, .has a flat bottom surface 19 for clamping apposition to the abutment-Harige 12 and a conical working surface 20 of suit' able pitch or slope meeting the rather-shallow cylindrical base-surface 21. For best embodiment of our invention, rather-deep grooves 2 2 are cut radially in the grinding-head, following the slope of the cone-surface, three such grooves being preferably provided at equal intervals. Of the opposed holding members 11 and 12 the grinding head 11 is desirably the removable one and it is preferably slip-iitted on the shank and driven toward abutment 12 by a clamp-nut.

In the construction shown the grinding head 11 has a smooth cylindrical bore 23 to ft neatly over the guide-surface 17 of the shank and has a hub-portion 24 on the upper face of the head so as both to elongate the bearing and to act as an integral spacingcollar against which the clamp-nut 25 works. Such clamp-nut 25, engaging the threadedportion of the shank, may be finger-manipulated to drive the inding head home, and for easy manipulation it is preferably made oflarger diameter than collar 24 and with a knurled periphery.

The renewable abrasive elementl 14- is of preformed cup shape, with the carborundum, emery, or other abrasive on itslexterior. Its bottom 26 is apertured as at 27 to slip tightly over the shank and be clamped between the grinding head and the abutment flange, the shank-groove 18 insuring that the cup bottom can lie flat. The flaring skirt-portion 28 is adapted tobear upon and be backed by the cone-surface 20 of the grinding head. For best embodiment of our invention such skirtportion 28 is flexible and stretchable or eX- pansible, although stiff enough to resist deformation from original shape and 1t 1s preformed to a pitch steeper than that of the head-surface 20. Satisfactory and inexpensive abrading elements may be provided by using ordinary emery cloth or nishing cloth to aord the outside surface-layer 29 and backing it with a layer 30 of dampened paper of absorbent quality such as blotting paper, united to the cloth by a coating 31 of adhesive such as liquid glass, cutting the composite sheet into disks as shown in Fig. 4f and molding and drying the same into requisite cup form. We prefer to form the cupskirt 28 with indented folds 32, positioned to intert in the grooves 22 of the grinding head and tapering in depth from the margin of the cup-skirt toward the cup-bottom. rfhe cup may, however, be molded without such grooves or folds, in the stated fashion, without wrinkling. Y

With the cup having requisite skirt-wall stiffness and springiness, it will be apparent that forcing the grinding head from the position shown in Fig. 1 to that shown in Fig. 2 will expand the skirt somewhat at its iiared edge, aiding in the insurance of snug, allover fit of the flaring surfaces of the cup with the conical surfaces of the grinding head and consequent accuracy in the functioning of the assembled tool. The tight clamping of the cup-bottom between the opposed surfaces of the grinding head and abutment-flange holds the removable abrasive element in place with requisite certainty, and its positioning against displacement on the grinding head is aided by the engagement of the folds 32 of the abrasive cup in the grooves 22 of the grinding head.

While we have herein described in some detail a particular embodiment of our invention which we have found to be markedly desirable and efficient, it will be understood by those skilled in the art that changes of details may be made without departure from the spirit and scope of our invention and within the scope of the appended claims.

We claim:

l. In a valve-grinding tool, the combination of a shank, a cupped element formed of an integral sheet of abrasive material and having a bottom portion, with a central opening therein of such size as to snugly receive said shank and having a Haring skirt portion, and confronting members on said shank having surfaces to clamp between them the bottom of said abrasive-element and one of said members having a cone surface to back up the skirt portion of the abrasive-element, the pitch of said skirt portion being steeper than that of said cone surface so that said skirt portion is stripped uniformly upon said vcone surface as said confronting members are clamped together, and one of said members being removable from the shank.

.2. In a valve-grinding tool, the combination of a shank having a circumferential groove, an abrasive-element formed from an integral sheet of abrasive material surrounding said shank and having a flat bottom por-- tion and a aring, expansible skirt portion, said bottom portion having a central opening therein through which said shank is passed and the rim of which is received in said groove, and confronting members on said shank having surfaces to clamp between them the bottom of said abrasive-element and one of said members having a cone surface to back up the skirt portion of the abrasive element, said cone surface being of less steep pitch than the flare of the pre-formed skirt to expand said skirt portion into snug and uniform engagement therewith as said confronting members are clamped together, one of said members being fixed to said shank and the other removable from the shank.

3. ln a valve-grinding tool, the combination of a shank, an abrasive-element normally cup-shaped and detachably surrounding said shank, said element having a circular bottom portion andan expansible, flared and continuous skirt portion traversed radially by indented folds, and confronting members on said shank having surfaces to clamp between them the bottom of said abrasive-element and one of said members having a cone surface to back up the skirt portion of the abrasiveelement, said cone surface having correspondingly-shaped spaces to receive said folds to maintain the contour of the element and to eect true-uniform and non-displaceable engagement between said skirt portion and cone surface as said confronting members are clamped together, and one of said members being removable from the shank.

4. fn a valve-grinding tool, the combination of a shank, an element formed from an integral sheet of abrasive material and having a bottom portion with a central opening to receive said shank and a flaring, expansible skirt portion, said skirt portion having one or more radial, tapering inward folds, and confronting members on said shank having surfaces to clamp between them the bottom of said abrasive element and one of said members having a cone surface to receive and support the skirt portion of the abrasive element, said cone surface being of less steep pitch than the normal iiare of the skirt-portion of said abrasive-element and traversed by one or more radial grooves to receive said element fold or folds, and one of said members being removable from the shank.

5. In a valve-grinding tool, the combination of a shank, a flexible, cupped abrasive element formed of an integral sheet of abrasive material and having a bottom portion with a central opening therein to receive said shank and an expansible flaring skirt portion, a fixed abutting flange on said shank having a surface to receive the bottom of the abrasive-element, a grinding-head slipfitted on said shank and having a surface to clamp said bottom of said abrasive-element against said abutment and a cone-surface to back up the skirt portion of said abrasiveelement, said element being indented radially at intervals and said cone-surface being recessed at like intervals to receive said element indent portions so that the general, normal shape of said element is maintained and the element is positively fixed in place when said grinding-head is clamped in position, and a clamp-nut engaging said shank and acting on said grinding-head to move it to clamping position.

6. An abrasive-element for a tool of the character described, including a continuous, integral sheet of abrasive material normally cup-shaped and having an apertured, circular fiat bottom and a Haring skirt, said skirt being of pressure-deformable, somewhatexpansible construction and having one or more inwardly extending, radial, tapered folds therein.

7. An abrading element for a tool of the character described which takes the form of an abrasive shell of slightly plastic material, comprising an integral circular sheet formed of permanently united layers of abrasive cloth and backing paper; said shell having a flat portion with a central openin therein and a conical skirt portion extending from said fiat portion, said conical portion having one or more inward, radial folds therein which extend from its free edge-and which taper toward said flat portion.

In testimony whereof, we have subscribed our names.

FREDERICK G. WACKER. HERMAN W. ZIMMERMAN. 

